The Lanarkshire side lost strike pair Henrik Ojamaa and Michael Higdon in the summer along with Humphrey, whose crosses were the ideal fodder for John Sutton during the returning forward's first spell working under McCall at Fir Park.
McCall has brought in the likes of Iain Vigurs and Paul Lawson, whose passing ability he feels can help them unlock defences, but he would still like a wide man on the right to complement James McFadden's creative spark.
McCall, whose team open their Scottish Premiership campaign against Hibernian at Easter Road tomorrow, said: "We're on the lookout for an out and-out right-sider, not someone who is left-footed because I want someone who can get to the dead-ball line and put crosses in.
"We have strikers who can score from crosses, Henri (Anier), Bob McHugh, big Sutty and Faddy. We need a bit of pace and width in certain games.
"What we have gained in certain areas, probably a little bit stronger defensively and a bit more experience, we have certainly lost out on the pace with Ojamaa, Chris Humphrey and Lawsy (Nicky Law) to an extent driving from the middle of the park.
"I still think we have a lot of good footballers in there, who can pass the ball and open teams up, and as we get a bit more sharper, I'm sure we will start creating more opportunities."
McCall was handed food for thought in his team selection during Thursday's 2-0 Europa League defeat by Kuban Krasnodar when left-back Zaine Francis-Angol performed promisingly in a wide midfield role.
"He can play high up, he can play as a wing-back and a full-back," McCall said. "Against a really good full-back, he gave him a difficult time.
"The lad got booked and maybe on another night he might have got sent off because he had another couple of fouls on him.
"He put in a great cross for big Sutton's header, which hit off the inside of the post and came out."